Make users members of the pulse group don't hurt but is useless:
- If the system is started at the user level, which is the default, the pulse group is not used at all.
- If it is started system wide (chmod 755 /etc/rc.d/rc.pulseaudio), in Slackware and derivatives the group to which a user should belong to be granted access to the pulse daemon is audio (set at compile time in the SlackBuild), which is already in the isgroupinsalix list.